This invention concerns a support for rolling rings on rolling stands having rolls supported as cantilevers, as set forth in the main claim.
To be more exact, this invention concerns an improved support to hold and position and to set in rotation and keep in rotation the rolling rings of rolls supported as cantilevers on a rolling stand.
Rolling stands having rolls supported as cantilevers are known whereby the rolling stands bear rolling rings with one or more rolling grooves, and these rings replace the normal rolls.
It is known that at the present time these rolling rings are made of a very hard material of a sintered type.
It is also known that these rolling rings are fitted and then clamped on appropriate supports, which have the purpose of holding and positioning the rolling rings reciprocally and of transmitting rotary motion to the rolling rings.
The rotary motion is normally transmitted by friction and not by means of pins or keying.
It is therefore obvious that these supports perform very important and essential functions in the working of a rolling stand.
A system for fitting the cantilever rolling rings on the supports 10 is therefore an essential part of the support so that the latter can perform its functions as well as possible; a preferred present system is the one shown in FIG. 1.
FIG. 1 shows a rolling ring 11 fitted to a shaft 16, which includes a first flange 12, a second flange 13 with a half-shaft 116 being comprised; the two shafts 16 and 116 rest against each other substantially along the line 15 of the coupling, which is located at an intermediate position along the length of the hole serving for the coupling of the rolling ring 11.
Threaded bolts 14 are used to clamp the second flange 13 against the first flange 12 and therefore to clamp the rolling ring 11 in an intermediate position.
Undercuts 17 are included in the first flange 12 and in the second flange 13 and act as pre-loading means in the clamping.
This solution under load entails a plurality of shortcomings, which reduce the life and capability of the known embodiment.
A first shortcoming is the breakages 18 which occur in the first flange 12.
A second shortcoming is the deflections 19 which take place in the first flange 12 and do not allow the rolling ring 11 to be positioned correctly; these deflections 19 remain as permanent strains.
A third shortcoming is the deflections 119 which occur in the second flange 13 and entail an incorrect positioning of the rolling ring 11; these deflections 119 too remain as permanent strains.
When a deflection becomes a permanent strain, the affected parts of the support 10 become unusable.
A fourth shortcoming is the reduced clamping torque which can be applied to the bolts 14.
A fifth shortcoming is the inability of the support 10 under given conditions to set the rolling ring 11 in rotation and therefore to make the rolling stand operational.
The documents GB-A-2,193,670 and GB-B-1,252,549 disclose a support for rolling rings on rolling stands with rolls supported as cantilevers, whereby a first flange extends along the whole length of the roll. However, the roll has a trapezoidal conformation and the thrust of the flanges does not create the strain according to the example of the attached FIG. 1. But this solution is very expensive owing to the special form of the roll, which in any event is fragile and unsuitable for heavy loads.
Document EP-A-0.301.286 discloses a roll made of a hard sintered metal and fitted to a shaft having two supports, one per side. This type of installation provides a roll with parallel lateral surfaces and with flanges having parallel lateral walls and consisting of an antifriction metal. This installation is not suitable to transmit great torque since the flanges bend and lose their capability of transmitting the load.